(1) Field of the Invention
This invention pertains to farming, and more specifically to an implement for tilling the surface of the soil of an agricultural field to reduce blowing sand and topsoil erosion. Farmers in areas where blowing sand occurs have ordinary skill in this art.
(2) Description of the Related Art
Topsoil in West Texas is sandy. After a heavy rain, the lighter portions of the sand within the soil rise to the surface of the ground. Dry winds cause the sand to blow in the Spring, injuring tender growing crops and causing soil erosion.
To prevent the sand from blowing, a tilling implement called a "sand fighter" has been developed. This implement is designed to turn up "divots," or clumps of damp soil, having heavier components than the dry surface soil, in an area of about four square inches per square foot of topsoil.
These sand fighters are designed as implements to be hauled behind a standard tractor, where they are towed by a chain or hitch. Because the implements are very inexpensive, a farmer may have one sand fighter dedicated to each plot of land, where the sand fighter is left on the plot of land when not in use. Although not heavy, it should be understood that the sand fighters are of large size, which inhibits easily moving them along public roads. Early sand fighters included a frame extending over a large distance, often traversing a strip of land 30 to 40 feet wide. One or more shafts extended over this 30 to 40 feet of land. Kickers spaced along the shaft every 6 to 12 inches included a bent prong extending radially from the shaft, adapted to penetrate the soil about one inch and kick up about one square inch of heavy, moist soil.
Later sand fighters were adapted to be carried on the power lifts of tractors, and could therefore be easily raised and lowered. Some sand fighters were built in sections, having two or more ends, or wings, which folded over. With its wings folded, such a sand fighter would be easier to turn at the end of the field and would be easier to transport over public roads. Such an arrangement is disclosed in WILKINS (U.S. Pat. No. 4,612,997).
One problem with previous sand fighters was that it was difficult to kick up the divots without destroying the young plants. STEVENS (U.S. Pat. No. 4,854,390) discloses an arrangement of a plurality of rotors mounted on a tool bar, with four spiders on each rotor. The implement was designed to travel along the crop rows rather than at an angle thereto as the previous practice. The rotors have a bearing at each end, and extend down between crop rows. As the rotors run through the furrows between beds, the young crops on the bed pass between the rotors, and thus are not disturbed as the sand fighter passes over the field. Due to the construction of the rotors, there is a limit as to how close the spiders can approach the young plants, and there is a significant amount of land close to the rows of young plants which remains untilled, and subject to unchecked blowing sand.
Another problem with previous sand fighters was that when the frames were in the folded position, to facilitate turning at the end of the rows and traveling between feeds, the folded portions of the sand fighter extended a great distance into the air, in other words, they were very high. This large height when in the folded position created the very distinctive habit of coming in contact with high voltage power lines.
The following patents are known to the Applicant and one or more of said patents might be considered relevant to this application:
______________________________________ HUXFORD 4,383,580 May 17, 1983 TAYLOR 1,535,058 Apr 21, 1925 HANSEN 2,604,027 Jul 22, 1952 STEPHENSON 2,750,724 Jun 19, 1956 GROENKE 3,255,830 Jun 14, 1966 GROENKE 3,321,028 May 23, 1967 SHULER, et al 3,844,358 Oct 29, 1974 KLINDWORTH 4,191,260 Mar 4, 1980 FRIGGSTAD 4,355,689 Oct 26, 1982 WILKINS 4,612,997 Sep 23, 1986 STEVENS 4,854,390 Aug 8, 1989 ______________________________________